P0302 Engine Code: Causes, Symptoms, and Solutions

The P0302 engine code can cause serious drivability issues, so addressing the underlying problem (or problems) immediately is essential. If your check engine light has turned on and the OBD-II scanner reads a P0302 code, here’s what you need to know to help resolve it.

What Does the P0302 Code Mean?

Diagnostic trouble code (DTC) P0302 stands for “Cylinder 2 Misfire Detected.” The code indicates that your car’s primary computer, known as the powertrain control module (PCM), has detected a misfire in cylinder 2.

Cylinder Numbering:

  • Ford V8: Cylinders 1-4 on the passenger side and 5-8 on the driver side.
  • Chevy or Dodge V8: Cylinders 1-3-5-7 on the driver side and 2-4-6-8 on the passenger side.
  • Four-Cylinder Inline Engines: Numbered 1-2-3-4 starting from the timing belt end of the engine.

How the PCM Detects Misfires

The PCM establishes a baseline of crankshaft position sensor pulses, usually during deceleration when the engine is driven by vehicle momentum through the transmission. This information, known as “Crank Relearn” or “Case Relearn” (also “Adaptive Numerator” by Chrysler), helps the PCM detect misfires by comparing live crankshaft pulses with the stored pattern. The PCM also uses the camshaft position sensor to identify which cylinder should be firing.

Possible Causes of the P0302 Code

A misfire in cylinder 2 can be caused by various factors, including:

  • Fuel Delivery Issues: Faulty fuel injector, damaged injector circuit.
  • Ignition System Problems: Failed coil pack, worn spark plug.
  • Engine Mechanical Issues: Sticking valve, weak piston rings.

If other misfire codes accompany P0302, the issue may affect multiple cylinders, such as a vacuum leak or low fuel pressure. Consistent misfires on one cylinder can cause the ECM/PCM to shut down the injector on that cylinder to protect the catalytic converter.

Common Symptoms of the P0302 Code

Symptoms of a P0302 code may include:

  • Check engine light is on or flashing.
  • Rough running engine.
  • Stalling.
  • Difficulty starting the engine.
  • Foul odor from the exhaust.
  • Decreased power.
  • Excessive fuel consumption.

Diagnosing the P0302 Code

Diagnosing a P0302 code requires looking at all potential causes. If you lack the necessary DIY auto repair experience and skills, have a professional mechanic check your vehicle. If you’re confident in your skills, the first step is proper diagnosis to identify the underlying issue.

Fixing the P0302 Code

There are no simple, umbrella solutions to most OBD-II trouble codes. The repair process can vary depending on the root cause and the vehicle’s make and model. Consult online auto repair resources and guides or get an ALLDATA single-vehicle subscription for more detailed instructions. Always check your owner’s manual before attempting any repairs.

Leave a Comment

Read more